Method of producing bituminous/polymer emulsion and product

Abstract

The present invention relates to bituminous polymer emulsions and more particularly to a novel method for producing such emulsions to produce a coating which yields superior flexiblity and water resistance. The method of producing the bituminous polymer consists in passing heated asphalt and a heated polymer emulsion through a colloid meal. The resultant emulsion may have up to 75% solids.

We claim: 
     
       1. A method of producing a flexible and water resistant modified asphaltic coating comprising: a. simultaneously passing asphalt heated to about 250° F. and a polymer emulsion of a monomer selected from the group consisting of ethylene/vinyl acetate and an acrylate heated to approximately 145° F. through a colloid mill producing an emulsion of asphalt within the water phase of the polymer emulsion with the product emulsion at a temperature of 160°-170° F.;   b. immediately cooling said product emulsion exiting said colloid mill to approximately 120° F.; and   c. simultaneously continuously agitating said product emulsion exiting said colloid mill while said product emulsion is cooling until said 120° F. temperature is reached.   
     
     
       2. A method as claimed in claim 1 including the step of: a. melting a high melting point wax melting at 156° to 165° F. into said asphalt while heating said asphalt.   
     
     
       3. A method as claimed in claim 1 wherein said emulsion polymer is ethylene/vinyl acetate which includes the structure: ##STR3## 
     
     
       4. A method as claimed in claim 1 wherein said polymer emulsion consists of a monomer mixture of approximately 65% vinyl acetate, 20% ethylene and 15% (2-ethylhexyl acrylate) polymerized in water and using a surfactant blend of nonionic and anionic surfactants typically and a protective colloid of hydroxylethyl cellulose. 
     
     
       5. A method as claimed in claim 2 wherein said asphalt and wax is blended in the proportion of 90%-10% by weight. 
     
     
       6. A method as claimed in claim 2 wherein the ratio of said asphalt in the asphalt/wax blend and solid polymer in the polymer emulsion is 1 to 1 by weight of asphalt to solid polymer. 
     
     
       7. A method as claimed in claim 1 including the step of adding a defoaming agent to said polymer emulsion after heating and prior to passing said emulsion through the colloid mill.   
     
     
       8. The flexible and water resistant bituminous/polymer emulsion coating obtained by the process steps comprising a. simultaneously passing asphalt heated to about 250° F. and a polymer emulsion of a monomer selected from the group consisting of ethylene/vinyl acetate and an acrylate heated to approximately 145° F. through a colloid mill producing an emulsion of asphalt within the water phase of the polymer emulsion with the product emulsion at a temperature of 160°-170° F.;   b. immediately cooling said product emulsion exiting said colloid mill to approximately 120° F.; and   c. simultaneously continuously agitating said product emulsion exiting said colloid mill while said product emulsion is cooling until said 120° F. temperature is reached.   
     
     
       9. The product of claim 8 wherein said emulsion polymer is an aqueous of ethylene/vinyl acetate.